attorney general wants to make sure election fraud will not occur. >> we have a right to require additional information to satisfy ourselves that someone is a citizen. >> >> reporter: right now, arizona requires proof of citizenship to register to vote in state elections. the supreme court will determine whether or not the state can demand proof of citizenship. >> specifically whether congress had the ability to provide for a simple male voter registration form that can be used in any state. this is about the basic right to vote. here in california, you don't have to show proof of u.s. citizenship to register to vote. all you have to do is sign your name on the line saying you are a u.s. citizen under penalty of perjury it's all done by the honor system. opponents say it disenfranchises voters. it's its already to get citizens to vote and see arizona's law as a roadblock. >> there are many barriers already in the way for the supreme court to put more barriers in the way of registered voters is not the way we want to go. we want to encourage civic participation and encourage people to come o